Organic light-emitting diode display

ABSTRACT

An organic light-emitting diode display is disclosed. In one aspect, the display includes a display unit located on the substrate and including a display area and a non-display area surrounding the display area, and a thin film encapsulation layer sealing the display unit. The display also includes a voltage line formed in the non-display area and surrounding the display area, a metal layer formed of the same material as the voltage line, and a dam surrounding the display area and contacting the voltage line. The voltage line includes a first voltage line disposed in one side of the display area. The first voltage line includes a pair of first end portions and a pair of first connectors respectively connected to the pair of first end portions and extending away from the display area. The metal layer is disposed between the pair of first connectors. The dam contacts the metal layer.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2015-0107415, filed on Jul. 29, 2015, in the Korean IntellectualProperty office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

Field

The described technology generally relates to an organic light-emittingdiode (OLED) display.

Description of the Related Technology

An OLED display generally includes a hole injection electrode, anelectron injection electrode, and an OLED disposed therebetween.Excitons are generated when holes emitted from the hole injectionelectrode and electrons emitted from the electron injection electrodecombine in the organic emission layer, and these excitons emit light.

OLED displays are designed to be driven with a low voltage andmanufactured to be light and thin. Also, these displays have favorablecharacteristics such as wide viewing angles, high contrast, and rapidrefresh rates and thus have drawn attention as next-generation displaydevices. However, since OLED characteristics are likely to degrade dueto environmental conditions like external moisture, oxygen, etc., theOLEDs should be protected against the environment.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect relates to OLED displays.

Another aspect is an OLED display that includes a substrate; a displayunit located on the substrate and including a display area and anon-display area outside the display area; a thin film encapsulationlayer for sealing the display unit; a voltage line formed in thenon-display area and surrounding the display area; and a dam unit havingat least a part contacting the voltage line, wherein the voltage lineincludes a first voltage line disposed to correspond to one side of thedisplay area, wherein the first voltage line includes a pair of firstend portions and a pair of first connection units respectively connectedto the pair of first end portions, wherein a metal layer including thesame material as that of the voltage line is disposed between the pairof first connection units, and wherein the dam unit includes at leasttwo dams and has at least a part contacting the metal layer.

The dam unit may include a first dam and a second dam that are spacedapart from each other, wherein the first dam surrounds the display area,and the second dam surrounds the first dam.

A height of the second dam may be higher than that of the first dam.

The metal layer may be insulated from the voltage line.

The display unit may include at least one thin film transistor, and themetal layer may be formed on the same layer as a source electrode and adrain electrode of the thin film transistor.

The metal layer may be located in a lower portion of the dam unit.

The display unit may include a thin film transistor, an organiclight-emitting device electrically connected to the thin filmtransistor, and a planarization layer disposed between the thin filmtransistor and the organic light-emitting device, and the dam unit isformed on the same layer as the planarization layer.

The display unit further may include a pixel-defining layer defining apixel area, and the dam unit may include a first layer formed on thesame layer as the planarization layer and a second layer formed on thesame layer as the pixel-defining layer.

The first layer and the second layer may be integrally formed.

The thin film encapsulation layer may include at least one inorganiclayer and at least one organic layer, and the at least one organic layermay be located inside the dam unit.

The voltage line may include a second voltage line surrounding the pairof first end portions and the other sides of the display area, and thesecond voltage line may include a pair of second end portions bent tosurround outer sides of the pair of first end portions and a pair ofsecond end portions in parallel to the pair of first end portions formedin the pair of second end portions.

The dam unit may contact the second voltage line outside of the othersides of the display area, and the dam unit may have a straight lineshape outside of the one side of the display area and simultaneouslycontacts the pair of second end portions, the pair of first connectionunits, and the metal layer.

The display unit may further include: a pad unit for applying anelectrical signal to the display area, the display unit may be disposedoutside of the one side of the display area, and the pair of firstconnection units and the pair of second connection units may beconnected to the pad unit.

The metal layer may be continuously formed with the first voltage line.

The first voltage line may extend to a dam formed outermost.

The voltage line may include a second voltage line surrounding the pairof first end portions and the other sides of the display area, and anouter side of the metal layer and an outer side of the second voltageline may be located on the same line outside of the one side of thedisplay area.

The thin film transistor may include an active layer, a gate electrode,a source electrode, and a drain electrode, a gate insulating layer maybe disposed between the active layer and the gate electrode, and aninterlayer insulating layer may be disposed between the gate electrodeand the source electrode and the drain electrode, the gate insulatinglayer and the interlayer insulating layer may extend to the non-displayarea, and the thin film encapsulation layer may include at least oneinorganic layer that contacts the gate insulating layer or theinterlayer insulating layer outside the dam unit.

The at least one inorganic layer may contact a top surface of thesubstrate by passing by an end portion of the interlayer insulatinglayer.

Another aspect is an organic light-emitting diode (OLED) display,comprising: a substrate; a display unit located on the substrate andcomprising a display area and a non-display area outside the displayarea; a thin film encapsulation layer sealing the display unit; avoltage line formed in the non-display area and surrounding the displayarea; a metal layer formed of the same material as the voltage line; anda dam having at least a part contacting the voltage line, wherein thevoltage line comprises a first voltage line disposed in one side of thedisplay area, wherein the first voltage line comprises a pair of firstend portions and a pair of first connectors respectively connected tothe pair of first end portions and extending away from the display area,wherein the metal layer is disposed between the pair of firstconnectors, and wherein the dam contacts the metal layer.

In the above OLED display, the dam comprises a first dam and a seconddam spaced apart from each other, wherein the first dam surrounds thedisplay area, and wherein the second dam surrounds the first dam.

In the above OLED display, the second dam has a height greater than thatof the first dam.

In the above OLED display, the metal layer is electrically insulatedfrom the voltage line.

In the above OLED display, the display unit comprises at least one thinfilm transistor (TFT), wherein the TFT comprises a source electrode anda drain electrode, and wherein the metal layer is formed on the samelayer as the source and drain electrodes.

In the above OLED display, the metal layer is located below the dam.

In the above OLED display, the display unit comprises a thin filmtransistor (TFT), an OLED electrically connected to the TFT, and aplanarization layer disposed between the TFT and the OLED, wherein thedam is formed on the same layer as the planarization layer.

In the above OLED display, the display unit further comprises apixel-defining layer defining a pixel area, wherein the dam comprises afirst layer formed on the same layer as the planarization layer and asecond layer formed on the same layer as the pixel-defining layer.

In the above OLED display, the first layer and the second layer areintegrally formed.

the thin film encapsulation layer is formed of at least one inorganiclayer and at least one organic layer, wherein the at least one organiclayer is located inside the dam.

In the above OLED display, the voltage line comprises a second voltageline surrounding the pair of first end portions, wherein the secondvoltage line comprises a pair of second end portions bent to at leastpartially surround outer sides of the pair of first end portions and apair of connectors in parallel to the pair of first connectors andextending from the pair of second end portions.

In the above OLED display, the dam contacts the second voltage lineoutside of the remaining sides of the display area, wherein a portion ofthe dam has a straight line shape and contacts the pair of second endportions, the pair of first connectors, and the metal layer.

In the above OLED display, the display unit further comprises a pad unitconfigured to apply an electrical signal to the display area, whereinthe pad unit is disposed in the non-display area, and wherein the pairof first connectors and the pair of second connectors are connected tothe pad unit.

In the above OLED display, the metal layer is integrally formed with thefirst voltage line.

In the above OLED display, the dam comprises a plurality of dams, andwherein the first voltage line extends to the outermost dam.

In the above OLED display, the voltage line comprises a second voltageline surrounding the pair of first end portions and the remaining sidesof the display area, wherein the metal layer and an outer side of thesecond voltage line overlap in the depth dimension of the OLED display.

In the above OLED display, the TFT comprises an active layer, a gateelectrode, a source electrode, and a drain electrode, wherein the OLEDdisplay further comprises: a gate insulating layer disposed between theactive layer and the gate electrode; and an interlayer insulating layerdisposed between the gate, source and drain electrodes, wherein the gateand interlayer insulating layers extend from the display area to thenon-display area, and wherein the thin film encapsulation layercomprises at least one inorganic layer contacting the gate insulatinglayer or the interlayer insulating layer outside the dam.

In the above OLED display, the at least one inorganic layer has aportion contacting a top surface of the substrate.

Another aspect is an organic light-emitting diode (OLED) display,comprising: a display unit comprising a display area and a non-displayarea surrounding the display area; a voltage line formed in thenon-display area and surrounding the display area; a plurality of damsformed in the non-display area and surrounding the display area; and ametal layer located adjacent to the voltage line, wherein the metallayer and the voltage line overlap the dams in the depth dimension ofthe OLED display.

In the above OLED display, the voltage line comprises a first voltageline disposed in one side of the display area, wherein the first voltageline comprises a pair of first end portions and a pair of firstconnectors respectively connected to the pair of first end portions,wherein the metal layer is disposed between the pair of firstconnectors, and wherein the dams overlap the first connectors in thedepth dimension of the OLED display.

In the above OLED display, the voltage line includes a second voltageline overlapping the dams.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of an OLED display according to anexemplary embodiment.

FIG. 2 is a schematic enlarged plan view of a region A of FIG. 1.

FIG. 3 is a schematic cross-sectional view taken along line II-II′ ofFIG. 2.

FIG. 4 is a cross-sectional view of a display unit according to anexemplary embodiment.

FIG. 5 is a cross-sectional view of an OLED display according to anotherexemplary embodiment.

FIG. 6 is a cross-sectional view of an OLED display according to anotherexemplary embodiment.

FIG. 7 is a cross-sectional view of an OLED display according to anotherexemplary embodiment.

FIG. 8 is a cross-sectional view of an OLED display according to anotherexemplary embodiment.

FIG. 9 is a schematic plan view of an OLED display according to anotherexemplary embodiment.

FIG. 10 is a schematic enlarged plan view of a region B of FIG. 9.

FIG. 11 is a schematic cross-sectional view taken along line X-X′ ofFIG. 11.

FIG. 12 is a cross-sectional view of an OLED display according toanother exemplary embodiment.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present exemplary embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

Since the described technology may have various modifications andseveral embodiments, exemplary embodiments are shown in the drawings andwill be described in detail. Advantages, features, and a method ofachieving the same will be specified with reference to the embodimentsdescribed below in detail together with the attached drawings. However,the embodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein.

The embodiments of the described technology will be described below inmore detail with reference to the accompanying drawings. Thosecomponents that are the same or are in correspondence are rendered thesame reference numeral regardless of the figure number, and redundantexplanations are omitted.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

Singular expressions, unless defined otherwise in contexts, includeplural expressions.

In the embodiments below, it will be further understood that the terms“comprise” and/or “have” used herein specify the presence of statedfeatures or components, but do not preclude the presence or addition ofone or more other features or components.

Also, in the drawings, for convenience of description, sizes of elementsmay be exaggerated or contracted. In other words, since sizes andthicknesses of components in the drawings are arbitrarily illustratedfor convenience of explanation, the following embodiments are notlimited thereto.

When an exemplary embodiment is implementable in another manner, apredetermined process order may be different from a described one. Forexample, two processes that are consecutively described may besubstantially simultaneously performed or may be performed in anopposite order to the described order. In this disclosure, the term“substantially” includes the meanings of completely, almost completelyor to any significant degree under some applications and in accordancewith those skilled in the art. Moreover, “formed, disposed or positionedover” can also mean “formed, disposed or positioned on.” The term“connected” includes an electrical connection.

FIG. 1 is a schematic plan view of an OLED display 1000 according to anexemplary embodiment. FIG. 2 is a schematic enlarged plan view of aregion A of FIG. 1. FIG. 3 is a schematic cross-sectional view takenalong line II-II′ of FIG. 2. FIG. 4 is a cross-sectional view of adisplay unit according to an exemplary embodiment.

Referring to FIGS. 1 through 4, the OLED display 1000 according to anexemplary embodiment includes a substrate 100, a display unit 200 on thesubstrate 100, a thin-film encapsulation layer 300 for sealing thedisplay unit 200, voltage lines 10 a and 20 formed in a non-display areaand surrounding a display area DA, and a dam unit (or dam) 50 a havingat least a part contacting the voltage lines 10 a and 20.

The substrate 100 may include various materials. According to anexemplary embodiment, the substrate 100 includes a SiO₂-basedtransparent glass material but is not limited thereto. The substrate 100may include a transparent plastic material. The plastic material may bean organic material selected from the group consisting ofpolyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI),polyethylene napthalate (PEN), polyethyleneterepthalate (PET),polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate(PC), cellulose triacetate (TAC), and cellulose acetate propionate(CAP), which are insulating organic materials.

When the OLED display 1000 is a bottom emission-type display device inwhich an image is formed in a direction of the substrate 100, thesubstrate 100 should be formed of a transparent material. However, whenthe OLED display 1000 is a top emission-type display device in which animage is formed in a direction away from the substrate 100, thesubstrate 100 does not need to include a transparent material. In thiscase, the substrate 100 may be formed of a metal. When the substrate 100includes a metal, the substrate 100 may include, but is not limited to,at least one of iron, chromium, manganese, nickel, titanium, molybdenum,stainless steel (SUS), Invar alloy, Inconel alloy, and Kovar alloy.

The display unit 200 may be formed on the substrate 100. The displayunit 200 may include the display area DA in which an image is formed andviewed by a user, and the non-display area, which is the perimeter ofthe display area DA.

An OLED may be disposed in the display area DA, and the voltage lines 10a and 20 may be disposed in the non-display region and supply power tothe OLED.

In the non-display area, a pad unit PAD may be further included andtransmit an electric signal to the display area DA from a power supply(not shown) or a signal generator (not shown).

The pad unit PAD may include a driver IC 410, a pad 430 that connectsthe driver IC 410 to a pixel circuit, and a fan out line 420.

The driver IC 410 may include a data driving unit (or data driver) forsupplying a data signal to the pixel circuit and various function unitsfor driving the pixel circuit. The driver IC 410 may be mounted on thesubstrate 100 as a chip on glass (COG) type. A connection terminal (notshown) that is electrically connected to the pad 430 formed on thesubstrate 100 may be provided to one side of the driver IC 410. Anadhesive material including a conductive ball and capable of electricalconnection may be disposed between the pad 430 and the connectionterminal (not shown) to bond the pad 430 and the connection terminal(not shown). Examples of the adhesive material may include ananisotropic conductive film, a self-organized conductive film, etc.

The pad 430 may be a part formed on the substrate 100 and electricallyconnected to the connection terminal of the driver IC 410. The pad 430may be electrically connected to the fan out line 420. As shown in FIG.1, the pad 430 may include a different layer from that of the fan outline 420 but is not limited thereto. The pad 430 may elongate from thefan out line 420 and be disposed on the same layer as the fan out line420. The pad 430 may include a layer or multilayers including at leastone material selected from molybdenum (Mo), aluminum (Al), copper (Cu),silver (Ag), and titanium (Ti).

The fan out line 420 may connect the pad 430 to the pixel circuit. Thefan out line 420 may be formed of the same material and formed on thesame layer as that of a gate electrode G. That is, the fan out line 420may be disposed on a gate insulation layer 210.

The display unit 200 will be described in more detail with reference toFIG. 4 below.

A buffer layer 110 may be formed on the substrate 100. The buffer layer110 may provide a flat surface on the substrate 100 and preventimpurities or moisture from permeating the substrate 100. For example,the buffer layer 110 is formed of inorganic materials such as siliconoxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminumnitride, titanium oxide, titanium nitride, etc., organic materials suchas polyimide, polyester, acryl, etc., or a stack structure including aplurality of materials among the above materials. The buffer layer 110may be formed on the display area DA and extend to the non-display area.

The display area DA may have, for example, a rectangular shape. Athin-film transistor TFT and the OLED electrically connected to thethin-film transistor TFT may be disposed in the display area DA.

The thin-film transistor TFT may include an active layer A, the gateelectrode G, a source electrode S, and a drain electrode D.

The thin-film transistor TFT is a top gate-type transistor in which theactive layer A, the gate electrode G, the source electrode S, and thedrain electrode D are sequentially formed in this order. However, theexemplary embodiment is not limited thereto and other various types ofthin-film transistors such as a bottom gate-type transistor may beemployed as the thin-film transistor TFT.

The active layer A may be formed of polysilicon and may include achannel area that is not doped with impurities and a source area and adrain area that are doped with impurities on both sides of the channelarea. In this regard, impurities may be different depending on a type ofthe thin-film transistor TFT and may be N type impurities or P typeimpurities.

After the active layer A is formed, the gate insulation layer 210 may beformed on the active layer A over the entire surface of the substrate100. The gate insulation layer 210 may include a multi-layer structureor a single layer formed of an inorganic material such as a siliconoxide or a silicon nitride. The gate insulation layer 210 may insulatethe active layer A from the gate electrode G disposed on the activelayer A. The gate insulation layer 210 may extend to not only thedisplay area DA but also to a part of the non-display area.

After the gate insulation layer 210 is formed, the gate electrode G maybe formed on the gate insulation layer 210. The gate electrode G may beformed using a photolithography process and an etching process.

The gate electrode G may be formed on the gate insulation layer 210. Thegate electrode G may be connected to a gate line (not shown) thatapplies an on/off signal to the thin film transistor TFT.

The gate electrode G may include a low resistance metal material. Thegate electrode G may include a single layer or multiple layers using,for example, at least one of aluminum (Al), platinum (Pt), palladium(Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium(Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca),molybdenum (Mo), titanium (Ti), tungsten (W), and copper (Cu), by takinginto account the adhesive strength between the gate electrode G and alayer adjacent thereto, the surface flatness and processability ofstacked layers, etc.

After the gate electrode G is formed, an interlayer insulation layer 230may be formed over the entire surface of the substrate 100. Theinterlayer insulation layer 230 may insulate between the sourceelectrode S and the drain electrode D and the gate electrode G. Theinterlayer insulation layer 230 may extend to not only the display areaDA but also a part of the non-display area.

The interlayer insulation layer 230 may be formed of an inorganicmaterial. According to an exemplary embodiment, the interlayerinsulation layer 230 is formed of a metal oxide or a metal nitride.Examples of the organic material may include a silicon oxide (SO₂), asilicon nitride (SiNx), a silicon oxynitride (SiON), an aluminum oxide(Al₂O₃), a titanium oxide (TiO₂), a tantalum oxide (Ta₂O₅), a hafniumoxide (HfO₂), and a zinc oxide (ZrO₂).

The interlayer insulation layer 230 may include a multi-layer structureor a single layer formed of an inorganic material such as silicon oxide(SiOx) and/or silicon nitride (SiNx). In some exemplary embodiments, theinterlayer insulation layer 230 may have a double layer structure ofSiOx/SiNy or SiNx/SiOy.

The source electrode S and the drain electrode D of the thin filmtransistor TFT may be disposed on the interlayer insulation layer 230.The source electrode S and the drain electrode D may each include asingle layer or multiple layers including, for example, at least one ofaluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium(Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium(Cr), nickel (Li), calcium (Ca), molybdenum (Mo), titanium (Ti),tungsten (W), and copper (Cu). The source electrode S and the drainelectrode D may be formed to contact an area of the active layer A.

A planarization layer 250 may be formed over the entire surface of thesubstrate 100 and cover the source electrode S and the drain electrodeD. The planarization layer 250 may remove a step formed by the thin filmtransistor TFT and planarize an upper surface of the substrate 100 andprevent malfunction of the OLED due to a lower uneven structure.

The planarization layer 250 may be formed of an insulation material. Forexample, the planarization layer 250 is formed of an inorganic material,an organic material, or an organic/inorganic composite material and hasa single layer or a multi-layer structure by using various depositionmethods. In some exemplary embodiments, the planarization layer 250 isformed of at least one material from among an acrylic resin(polyacrylates resin), an epoxy resin, a phenolic resin, a polyamideresin, a polyimide resin, an unsaturated polyester resin, apolyphenylene ether resin, a polyphenylene sulfide resin, and abenzocyclobutene (BCB).

The OLED may be provided on the planarization layer 250. The OLED mayinclude a pixel electrode 281, an intermediate layer 283 including anorganic emissive layer, and an opposite electrode 285. As shown in FIG.4, the pixel electrode 281 may be electrically connected to the drainelectrode D.

The pixel electrode 281 and/or the opposite electrode 285 may include atransparent electrode or a reflective electrode. When the pixelelectrode 281 and/or the opposite electrode 285 include a transparentelectrode, the transparent electrode may include ITO, IZO, ZnO, orIn₂O₃. When the pixel electrode 281 and/or the opposite electrode 285include a reflective electrode, the reflective electrode may include areflective layer including Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or acompound thereof and a transparent layer including ITO, IZO, ZnO, orIn₂O₃. In some exemplary embodiments, the pixel electrode 281 or theopposite electrode 285 may have an ITO/Ag/ITO structure.

The pixel electrode 281 may be formed on the planarization layer 250 andelectrically connected to the thin film transistor TFT via a contacthole formed in the planarization layer 250. For example, the pixelelectrode 281 is a reflective electrode. For example, the pixelelectrode 281 includes a reflective film formed of Ag, Mg, Al, Pt, Pd,Au, Ni, Nd, Ir, Cr, or a combination thereof, and a transparent orsemi-transparent electrode layer formed on the reflective film. Thetransparent or semi-transparent electrode layer may include at least oneof indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO),indium oxide (In₂O₃), indium gallium oxide (IGO), and aluminum zincoxide (AZO).

The opposite electrode 285 disposed opposite the pixel electrode 281 maybe a transparent or semi-transparent electrode, and may include a metalthin film with a low work function such as Li, Ca, LiF/Ca, LiF/Al, Al,Ag, Mg, or a combination thereof. An auxiliary electrode layer or a buselectrode may be further formed on the metal thin film by using amaterial for forming a transparent electrode, e.g., ITO, IZO, ZnO,In₂O₃, or the like. Thus, the opposite electrode 285 may allow lightemitted from the organic emission layer included in the intermediatelayer 283 to pass therethrough. That is, the light emitted from theorganic emission layer may be reflected directly or via the pixelelectrode 281, which is a reflective electrode, and emitted toward theopposite electrode 285.

However, the display unit 200 according to the present embodiment is notlimited to a top emission-type display device and may be a bottomemission-type display device in which light emitted from the organicemission layer is emitted toward the substrate 100. In this case, thepixel electrode 281 may be a transparent or semi-transparent electrodeand the opposite electrode 285 may be a reflective electrode. Also, thedisplay unit 200 according to the present embodiment may be a dualemission-type display device in which light is emitted in bothdirections of front and bottom surfaces thereof.

A pixel-defining film 270 formed of an insulating material may bedisposed on the opposite electrode 285. The pixel-defining film 270 mayinclude at least one organic insulating material selected from the groupconsisting of polyimide, polyamide, acryl resin, benzocyclobutene, andphenol resin by spin coating or the like.

The pixel-defining film 270 may function to define a pixel area and anon-pixel area. The pixel-defining film 270 may be formed on thesubstrate 100 and include an opening partially exposing the pixelelectrode 281. As shown in FIG. 3, the thin film encapsulation layer 300may seal the display unit 200 and prevent external oxygen and moisturefrom permeating into the display unit 200. The thin film encapsulationlayer 300 may include a plurality of organic layers 330 and a pluralityof inorganic layers 310. The organic layers 330 and the inorganic layers310 may be alternately stacked to form a multilayer structure. Anexample of the thin film encapsulation layer 300 including two organiclayers 330 a and 330 b and two inorganic layers 310 a and 310 b isillustrated in FIG. 3 but the exemplary embodiments are not limitedthereto.

The organic layers 330 a and 330 b may each include, for example, atleast one of acryl-based resin, methacryl-based resin, polyisoprene,vinyl-based resin, epoxy-based resin, urethane-based resin,cellulose-based resin, and perylene-based resin.

The inorganic layers 310 a and 310 b may each include, for example, atleast one of silicon nitride, aluminum nitride, zirconium nitride,titanium nitride, hafnium nitride, tantalum nitride, silicon oxide,aluminum oxide, titanium oxide, tin oxide, cerium oxide, and siliconoxynitride (SiON).

As shown in FIG. 1, the voltage lines 10 a and 20 surrounding thedisplay area DA and the dam unit 50 a may be disposed in the non-displayarea outside the display area DA.

The voltage lines 10 a and 20 may be formed of the same materials asthose of the source electrode S and the drain electrode D. The voltagelines 10 a and 20 may include the first voltage line 10 a and the secondvoltage line 20. According to an exemplary embodiment, the first voltageline 10 a is a driving voltage line ELVDD, and the second voltage line20 may be a common voltage line ELVSS. The second voltage line 20 may beconnected to the opposite electrode 285.

The first voltage line 10 a may be disposed to correspond to at leastone side of the display area DA. The first voltage line 10 a may includea pair of first end portions 11 formed in parallel to one side of thedisplay area DA. In this regard, the at least one side corresponding tothe first voltage line 10 a may be a side adjacent to the pad unit PAD.

The second voltage line 20 may surround the pair of first end portions11 of the first voltage line 10 a and the other sides of the displayarea DA.

The second voltage line 20 may include a pair of second end portions 21bent to cover outer sides of the pair of first end portions 11. Each ofthe first end portions 11 may be disposed between the display area DAand the pair of second end portions 21.

The first voltage line 10 a may include a pair of first connection units(or connectors) 12 a. The second voltage line 20 may include a pair ofsecond connection units 22. The pair of first connection units 12 a mayextend in a direction perpendicular to (or crossing) the pair of firstend portions 11. The pair of second connection units 22 may be formed inparallel to the pair of first connection units 12 a from the pair ofsecond end portions 21.

The pair of first connection units 12 a and the pair of secondconnection units 22 may be connected to the pad unit PAD outside the atleast one side of the display area DA.

At least a part of the dam unit 50 a may be formed to contact the firstvoltage line 10 a and/or the second voltage line 20.

The dam unit 50 a may surround and be integrally connected around foursides of the display area DA outside the display area DA. That is, thedam unit 50 a may continuously surround the four sides of the displayarea DA in a ring shape.

The dam unit 50 a may prevent flow of an organic material along an edgeof the substrate 100 when the organic layers 330 of the thin filmencapsulation layer 300 for sealing the display unit 100 are formed,thereby preventing formation of edge tails of the organic layers 330.

As shown in FIG. 3, the organic layers 330 of the thin filmencapsulation layer 300 may be formed larger than the inorganic layers310. In this regard, the dam unit 50 a may prevent flow of the organicmaterial along the edge of the substrate 100 when the organic layers 330are formed. The organic layers 330 may be disposed inside the dam unit50 a.

According to an exemplary embodiment, the inorganic layers 310 extendand contact each other outside the dam unit 50 a. At least one of theinorganic layers 310 may contact the gate insulation layer 210 or theinterlayer insulation layer 230 outside the dam unit 50 a, therebypreventing permeation of external moisture into a side surface of thethin film encapsulation layer 300 and improving the adhesive strength ofthe thin film encapsulation layer 300.

According to an exemplary embodiment, outside the dam unit 50, at leastone of the inorganic layers 310 contacts a top surface of the substrate100 by passing by an end portion of the interlayer insulation layer 230and may contact side surfaces of the gate insulation layer 210 and theinterlayer insulation layer 230. Thus, edges of the inorganic layers 310may be separated, thereby preventing the weakening and removal of anencapsulation characteristic of the thin film encapsulation layer 300.

The dam unit 50 a of the OLED display 1000 according to the presentembodiment may include at least two or more dams.

According to an exemplary embodiment, as shown in FIGS. 1 through 3, thedam unit 50 a includes a first dam 51 a and a second dam 53 a spacedapart from the first dam 51 a by a predetermined distance and formedoutside the first dam 51 a.

The dam unit 50 a may include at least two dams, thereby effectivelyblocking reflow of an organic material and preventing flow of an organiclayer when only one dam is provided.

Although FIGS. 1 through 3 illustrate embodiments in which the dam unit50 a includes the first dam 51 a and the second dam 53 a, the number ofdams is not limited thereto as long as at least two are provided.

Although the first dam 51 a and the second dam 53 a have the same heightin the embodiments of FIGS. 1 through 3, when two or more dams areformed, the height of the dam unit 50 a may increase toward the outsideof the substrate 10.

The organic layers 330 of the thin film encapsulation layer 300 of theOLED display 1000 according to the present embodiment may block anorganic material from spreading and overflowing due to the dam unit 50 awhen the organic layers 330 are formed inside the first dam 51 a locatedinnermost on the substrate 100.

That is, the dam unit 50 a may provide a double dam including the firstdam 51 a and the second dam 53 a, thereby blocking an organic layer fromspreading and overflowing due to the first dam 51 a, and thus, noorganic layers may be formed between the first dam 51 a and the seconddam 53 a.

No organic layers may be formed between the first dam 51 a and thesecond dam 53 a, thereby efficiently preventing permeation of externalmoisture.

The dam unit 50 a may include an organic material. According to anexemplary embodiment, the dam unit 50 a may include at least one organicinsulating material selected from the group consisting of polyimide,polyamide, acryl resin, benzocyclobutene, and phenol resin.

A metal layer 30 a may be formed between the pair of first connectionunits 12 a of the first voltage line 10 a. As shown in FIG. 3, the metallayer 30 a may be located below the dam unit 50 a to contact the damunit 50 a.

The metal layer 30 a may thus improve the adhesive strength of the damunit 50 formed between the pair of first connection unit 12 a.

When the dam unit 50 a includes an organic material, the adhesivestrength of the organic material of the dam unit 50 a with respect to aninorganic material is weak. Thus, when the dam unit 50 a adheres to theinorganic material, a separation phenomenon may occur, and externalmoisture or oxygen may permeate, and thus the OLED may be damaged.

In the OLED display 1000 according to the present embodiment, the damunit 50 a may be integrally connected and continuously surround foursides of the display area DA, and the metal layer 30 a may contact alower portion of the dam unit 50 a between the pair of first connectionunits 12, and thus the adhesive strength of the dam unit 50 a may beimproved.

An area in which the metal layer 30 a is formed is not limited. Thus, aslong as at least a part of the metal layer 30 a is below the dam unit50, the metal layer may be formed between the pair of first connectionunits 12 a without limitation.

According to an exemplary embodiment, the metal layer 30 a may be formedwith the first voltage line 10 a. Thus, the metal layer 30 a may beformed on the same layer and may be formed of the same material as thefirst voltage line 10 a.

According to an exemplary embodiment, the metal layer 30 a may be formedof at least one of aluminum (Al), platinum (Pt), palladium (Pd), silver(Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium(Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo),titanium (Ti), tungsten (W), and copper (Cu).

As another selective embodiment, the metal layer 30 a is formed with thesource electrode S and the drain electrode D of the thin film transistorTFT. Thus, the metal layer 30 a may be formed on the same layer and mayinclude the same material as the source electrode S and the drainelectrode D.

As shown in FIG. 3, the dam unit 50 a is formed on the same layer andformed of the same material as the planarization layer 250.

The metal layer 30 a may be formed below the dam unit 50 a and thus thelower portion of the dam unit 50 a may contact the metal layer 30 a. Thedam unit 50 a may be formed above the metal layer 30 a and havesubstantially the same height as that of the planarization layer 250.However, the height of the dam unit 50 is not limited thereto.

According to an exemplary embodiment, the dam unit 50 a is formed of anorganic insulating material including at least one material from amongan acrylic resin (polyacrylates resin), an epoxy resin, a phenolicresin, a polyamide resin, a polyimide resin, an unsaturated polyesterresin, a polyphenylene ether resin, a polyphenylene sulfide resin, and abenzocyclobutene (BCB).

As shown in FIG. 1, the dam unit 50 a of the OLED display 1000 accordingto the present embodiment may be formed to contact the second voltageline 20 on at least three sides of the display area DA.

That is, the second dam 53 a formed outermost in the dam unit 50 a maybe formed to contact an edge of the second voltage line 20 on at leastthree sides of the display area DA.

On one side of the display area DA corresponding to a side in which thefirst end portions 11 of the first voltage line 10 a are disposed, thedam unit 50 a surrounding the display area DA may be integrally andcontinuously connected and may have at least a part contacting thesecond end portions 21. In other parts of the dam unit 50 a, at least apart of the dam unit 50 a may contact the first connection units 12. Inthe other parts of the dam unit 50 a, at least a part of the dam unit 50a may contact the metal layer 30 a.

Therefore, at least three sides of the dam unit 50 a including foursides in the ring shape may contact the second voltage line 20, and theone side thereof may contact the second end portions 21, the firstconnection units 12 a, and the metal layer 30 a, thereby improving theadhesive strength of the dam unit 50 a.

FIG. 5 is a cross-sectional view of an OLED display 2000 according toanother exemplary embodiment. The same reference numerals between FIGS.1 through 4 and 5 denote the same elements, and thus redundantdescriptions thereof are omitted for brevity of explanation.

A dam unit 50 b of the OLED display 2000 according to the presentembodiment may have the same function as that of the dam unit 50 a ofthe OLED display 1000 shown in FIGS. 1 through 3, and thus thedifferences therebetween will now be described.

The dam unit 50 b may include at least two dams, and may be integrallyconnected and surround four sides of the display area DA outside thedisplay area DA. That is, the dam unit 50 b may continuously surroundthe four sides of the display area DA in a ring shape.

The dam unit 50 b may contact the metal layer 30 a between the pair offirst connection units 12 (see FIG. 1), and thus the adhesive strengthof the dam unit 50 b may be improved, thereby reducing a probabilitythat external moisture or oxygen may permeate and improving thereliability of the OLED.

According to an exemplary embodiment, the dam unit 50 b includes a partformed on the same layer as the planarization layer 250 and a partformed on the same layer as the pixel-defining layer 270.

That is, when the planarization layer 250 is formed, the part of the damunit 50 b may be formed on the same layer as the planarization layer250, and, when the pixel-defining layer 270 is formed, the part of thedam unit 50 b may be formed on the same layer as the pixel-defininglayer 270.

The part of the dam unit 50 b formed on the same layer as thepixel-defining layer 270 may be formed of the same material as that ofthe pixel-defining layer 270. According to an exemplary embodiment, thepart of the dam unit 50 b is formed of at least one organic insulatingmaterial selected from the group consisting of polyimide, polyamide,acryl resin, and benzocyclobutene.

The part of the dam unit 50 b formed on the same layer as theplanarization layer 250 and the part of the dam unit 50 b formed on thesame layer as the pixel-defining layer 270 may be integrally formed.

The organic layer 330 may be blocked from spreading and overflowing by afirst dam 51 b, and thus the organic layer 330 may not be formed betweenthe first dam 51 b and a second dam 53 b.

No organic layers may be formed between the first dam 51 b and thesecond dam 53 b, and the organic layer 330 may be formed inside thefirst dam 51 b, thereby efficiently preventing permeation of externalmoisture.

As shown in FIG. 5, the dam unit 50 b may be formed above the metallayer 30 a and have the same height as those of the planarization layer250 and the pixel-defining layer 270. However, the height of the damunit 50 b is not limited thereto.

According to an exemplary embodiment, the first dam 51 b and the seconddam 53 b are formed to have different heights. That is, a height of thesecond dam 53 b located outside the substrate 100 may be relativelyhigher than that of the first dam 51 b.

FIG. 6 is a cross-sectional view of an OLED display 3000 according toanother exemplary embodiment. The same reference numerals between FIGS.1 through 4 and 6 denote the same elements, and thus redundantdescriptions thereof are omitted for brevity of explanation.

A dam unit 50 c of the OLED display 3000 according to the presentembodiment may have the same function as that of the dam units 50 a and50 b described above, and thus the differences therebetween will now bedescribed for convenience of description.

The dam unit 50 c of the OLED display 3000 according to the presentembodiment may include a first dam 51 c and the second dam 53 b havingdifferent heights. That is, a height of the second dam 53 b may behigher than that of the first dam 51 c.

In this case, the first dam 51 c may include the same material as thepixel-defining layer 270 when the pixel-defining layer 270 is formed,and a lower portion of the second dam 53 b may include the same materialas that of the planarization layer 250 when the planarization layer 250is formed, and then, when the pixel-defining layer 270 is formed, anupper portion of the second dam 53 b may include the same material asthat of the pixel-defining layer 270 with the first dam 51 c.

That is, the dam unit 50 c may include the same material as that of theplanarization layer 250 and/or the pixel-defining layer 270 when theplanarization layer 250 and/or the pixel-defining layer 270 is formed.In this case, the height and the material of the dam unit 50 c are notlimited.

According to an exemplary embodiment, a part of the second dam 53 bformed on the same layer as the planarization layer 250 and a partthereof formed on the same layer as the pixel-defining layer 270 mayinclude the same material so that lower and upper portions of the seconddam 53 b may be integrally formed.

No organic layers may be formed between the first dam 51 c and thesecond dam 53 b, and the organic layer 330 may be formed inside thefirst dam 51 c, thereby efficiently preventing permeation of externalmoisture.

FIG. 7 is a cross-sectional view of an OLED display 4000 according toanother exemplary embodiment. The same reference numerals between FIGS.1 through 4 and 7 denote the same elements, and thus redundantdescriptions thereof are omitted for brevity of explanation.

A metal layer 30 b of the OLED display 4000 according to the presentembodiment may be formed only in a lower portion of the dam unit 50 a.That is, the metal layer 30 b may be completely located in the lowerportion of the dam unit 50 to contact the dam unit 50 a.

According to the present embodiment, the metal layer 30 b may be formedbetween an inorganic layer such as the gate insulating layer 210, theinterlayer insulating layer 230, etc. and the dam unit 50 a, therebyimproving the adhesive strength of the dam unit 50 a and effectivelyblocking permeation of external moisture or oxygen to improve thereliability of the OLED.

According to an exemplary embodiment, the metal layer 30 b may be formedon the same layer and include the same material as that of the sourceelectrode S and the drain electrode D of the thin film transistor TFT.

The dam unit 50 a may include the first dam 51 a and the second dam 53 aand may be formed on the same layer and include the same material asthat of the planarization layer 250.

As shown in FIG. 7, the dam unit 50 a has substantially the same heightas that of the planarization layer 250 but the height of the dam unit 50a is not limited thereto. According to an exemplary embodiment, theheight of the second dam 53 a may be greater than that of the first dam51 a outside the substrate 100.

FIG. 8 is a cross-sectional view of an OLED display 5000 according toanother exemplary embodiment. The same reference numerals between FIGS.1 through 5 and 8 denote the same elements, and thus redundantdescriptions thereof are omitted for brevity of explanation.

In the OLED display 5000 according to the present exemplary embodiment,the metal layer 30 b is completely located in a lower portion of the damunit 50 b and contacts the dam unit 50 b. That is, the metal layer 30 bmay be formed only in an area in which the dam unit 50 b is formed.

The metal layer 30 b may be formed in a lower portion of the area inwhich the dam unit 50 b is formed, thereby improving the adhesivestrength of the dam unit 50 b and effectively blocking permeation ofexternal moisture or oxygen to improve the reliability of the OLED.

According to an exemplary embodiment, the metal layer 30 b is formed onthe same layer and formed of the same material as that of the firstvoltage line 10 a.

As another selective embodiment, the metal layer 30 b is formed on thesame layer and formed of the same material as that of the sourceelectrode S and the drain electrode D of the thin film transistor TFT.

The dam unit 50 a may include the first dam 51 b and the second dam 53 band, according to an exemplary embodiment, may include a part formed onthe same layer as the planarization layer 250 and a part formed on thesame layer as the pixel-defining layer 270.

As shown in FIG. 8, the first dam 51 b and the second dam 53 b may havethe same height but a height of the dam unit 51 b is not limitedthereto. The height of the second dam 53 b located outside of thesubstrate 100 may be relatively higher than that of the first dam 51 b.

According to an exemplary embodiment, when the planarization layer 250is formed, a lower portion of the dam unit 53 b may be formed with theplanarization layer 250, and then, when the pixel-defining layer 270 isformed, the first dam 51 b and an upper portion of the second dam 53 bmay be formed with the pixel-defining layer 270.

According to an exemplary embodiment, the part of the dam unit 51 bformed on the same layer as the planarization layer 250 and the part ofthe dam unit 51 b formed on the same layer as the pixel-defining layer270 are formed of the same material and integrally formed.

FIG. 9 is a schematic plan view of an OLED display 6000 according toanother exemplary embodiment. FIG. 10 is a schematic enlarged plan viewof a region B of FIG. 9. FIG. 11 is a schematic cross-sectional viewtaken along line X-X′ of FIG. 11.

The same reference numerals between FIGS. 1 through 4 and FIGS. 9through 11 denote the same elements, and thus redundant descriptionsthereof are omitted for brevity of explanation.

The OLED display 6000 according to the present exemplary embodiment mayinclude the substrate 100, the display unit 200 on the substrate 100,the thin-film encapsulation layer 300 for sealing the display unit 200,voltage lines 10 b and 20 formed in a non-display area and surrounding adisplay area DA, and a dam unit 50 having at least a part contacting thevoltage lines 10 b and 20.

The first voltage line 10 b may be disposed to correspond to at leastone side of the display area DA. In this regard, the at least one sidecorresponding to the first voltage line 10 b may be a side adjacent tothe pad unit PAD.

The first voltage line 10 b may include a pair of first connection units12 b connected to the pad unit PAD.

A metal layer may be disposed between the pair of first connection units12 b. The dam unit 50 a may contact the metal layer between the firstconnection units 12 b and may be integrally connected and continuouslysurround the display area DA.

As shown in FIG. 9, the metal layer of the OLED display 6000 accordingto the present embodiment is formed by extending the first voltage line10 b.

That is, the metal layer may not be provided between the firstconnection units 12 b but may be formed by extending the first voltageline 10 b to a blank area between the first connection units 12 b whenthe first voltage line 10 b is formed, so that a lower portion of thedam unit 50 may contact the first voltage line 10 b between the firstconnection units 12 b.

According to an exemplary embodiment, the first voltage line 10 b isformed by extending in a way that metal is filled between the firstconnection units 12 b without an empty space.

The first voltage line 10 b may be formed by extending to an area inwhich a dam is at least formed outermost the dam unit 50 a.

According to an exemplary embodiment, when the dam unit 50 a includesthe first dam 51 a and the second dam 53 a, the dam unit 50 a is formedby extending to an area in which the second dam 53 a is formed. Thus,lower portions of the first dam 51 a and the second dam 53 a may beadhered to the first voltage line 10 b.

In the OLED display 6000 according to the present exemplary embodiment,the dam unit 50 a completely contacts a lower portion of the firstvoltage line 10 b between the first connection units 12 b, therebyimproving the adhesive strength of the dam unit 50 a to reduce aprobability that external moisture or oxygen may permeate and improvingthe reliability of the OLED.

The voltage lines 10 b and 20 may include the second voltage line 20.The second voltage line 20 may include the pair of second end portions21 bent to cover outer sides of the pair of first end portions 11. Eachof the first end portions 11 may be disposed between the display area DAand the pair of second end portions 21.

The second voltage line 20 may include the pair of second connectionunits 22. The pair of first connection units 12 b may extend in adirection perpendicular to (or crossing) the pair of first end portions11. The pair of second connection units 22 may be formed in parallel tothe pair of first connection units 12 b and extend from the pair ofsecond end portions 21.

The pair of first connection units 12 b and the pair of secondconnection units 22 may be connected to the pad unit PAD outside the atleast one side of the display area DA.

According to an exemplary embodiment, outer sides of the first voltageline 10 b and the second voltage line 20 are located on the same lineoutside the display area DA of a side in which the first end portions 11are disposed.

That is, the outer side of the first voltage line 10 b may extend to theouter side of the second end portions 21 outside of the side in whichthe first end portions 11 are disposed in outer sides of four sides ofthe display area DA so that the outer sides of the first voltage line 10b and the second voltage line 20 may be located on the same line.

As shown in FIG. 11, the dam unit 50 a is formed on the same layer andformed of the same material as that of the planarization layer 250.

The first dam 51 a and the second dam 53 a may have the same height buta height of the dam unit 50 a is not limited thereto. The height of thesecond dam 53 a located outside of the substrate 100 may be relativelyhigher than that of the first dam 51 a.

As shown in FIG. 11, the first voltage line 10 b extends to a lowerportion of the second dam 53 a, and the first voltage line 10 b isprovided between the dam unit 50 a and a lower inorganic layer, and thusthe dam unit 50 a may contact the first voltage line 10 b formed of ametal material, thereby improving the adhesive strength of the dam unit50 a.

FIG. 12 is a cross-sectional view of an OLED display 7000 according toanother exemplary embodiment. The same reference numerals between FIGS.1 through 6 and 12 denote the same elements, and thus redundantdescriptions thereof are omitted for brevity of explanation.

In the OLED display 7000 according to the present exemplary embodiment,the first voltage line 10 b extends to an area in which the second dam53 b is formed, and the first voltage line 10 b is provided between thedam unit 50 c and a lower inorganic layer, and thus the dam unit 50 cmay contact the first voltage line 10 b formed of a metal material,thereby improving the adhesive strength of the dam unit 50 c.

In the OLED display 7000 according to the present exemplary embodiment,the dam unit 50 c includes the first dam 51 c and the second dam 53 bthat have different heights. That is, the height of the second dam 53 blocated outside of the substrate 100 may be greater than that of thefirst dam 51 c.

That is, when the planarization layer 250 is formed, a lower portion ofthe dam unit 53 b may be formed with the planarization layer 250, andthen, when the pixel-defining layer 270 is formed, the first dam 51 cand an upper portion of the second dam 53 b may be formed with thepixel-defining layer 270.

According to an exemplary embodiment, a part of the dam unit 51 b formedon the same layer as the planarization layer 250 and a part of the damunit 51 b formed on the same layer as the pixel-defining layer 270 areformed of the same material and integrally formed.

No organic layers may be formed between the first dam 51 c and thesecond dam 53 b, and the organic layer 330 may be formed inside thefirst dam 51 c, thereby efficiently preventing permeation of externalmoisture.

A lower portion of the second dam 53 b formed on the same layer as theplanarization layer 250 and an upper portion thereof formed on the samelayer as the pixel-defining layer 270 may be formed of the same materialand integrally formed.

As described above, according to the one or more of the exemplaryembodiments, reliability is improved by effectively preventing externalmoisture or oxygen from permeating.

It should be understood that exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exemplaryembodiment should typically be considered as available for other similarfeatures or aspects in other exemplary embodiments.

While the inventive technology has been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. An organic light-emitting diode (OLED) display,comprising: a substrate; a display unit located on the substrate andcomprising a display area and a non-display area outside the displayarea; a thin film encapsulation layer sealing the display unit; a firstvoltage line disposed in the non-display area and arranged to correspondto one side of the display area, wherein the first voltage linecomprises a first side facing the display area and a second sideopposite to the first side, and a pair of first protrusions protrudingfrom the second side; a second voltage line disposed in the non-displayarea and surrounding at least three sides of the display area; a metallayer separated from the first and second voltage lines and disposedbetween the pair of first protrusions; and a dam surrounding the displayarea, wherein the dam overlaps the first voltage line, the secondvoltage line and the metal layer, and wherein the second voltage linecomprises a pair of second end portions bent to at least partiallysurround outer sides of a pair of first end portions of the firstvoltage line and a pair of connectors in parallel to the pair of firstprotrusions and extending from the pair of second end portions.
 2. TheOLED display of claim 1, wherein the dam comprises a first dam and asecond dam spaced apart from each other, wherein the first dam surroundsthe display area, and wherein the second dam surrounds the first dam. 3.The OLED display of claim 2, wherein the second dam has a height greaterthan that of the first dam.
 4. The OLED display of claim 1, wherein themetal layer is electrically insulated from the second voltage line. 5.The OLED display of claim 4, wherein the display unit comprises at leastone thin film transistor (TFT), wherein the TFT comprises a sourceelectrode and a drain electrode, and wherein the metal layer is formedon the same layer as the source and drain electrodes.
 6. The OLEDdisplay of claim 4, wherein the metal layer is located below the dam. 7.The OLED display of claim 1, wherein the display unit comprises a thinfilm transistor (TFT), an OLED electrically connected to the TFT, and aplanarization layer disposed between the TFT and the OLED, and whereinthe dam is formed on the same layer as the planarization layer.
 8. TheOLED display of claim 7, wherein the display unit further comprises apixel-defining layer defining a pixel area, and wherein the damcomprises a first layer formed on the same layer as the planarizationlayer and a second layer formed on the same layer as the pixel-defininglayer.
 9. The OLED display of claim 8, wherein the first layer and thesecond layer are integrally formed.
 10. The OLED display of claim 1,wherein the thin film encapsulation layer is formed of at least oneinorganic layer and at least one organic layer, and wherein the at leastone organic layer is located inside the dam.
 11. The OLED display ofclaim 1, wherein the dam contacts the second voltage line outside of theremaining sides of the display area, and wherein a portion of the damhas a straight line shape and contacts the pair of second end portions,the pair of first protrusions, and the metal layer.
 12. The OLED displayof claim 1, wherein the display unit further comprises a pad unitconfigured to apply an electrical signal to the display area, whereinthe pad unit is disposed in the non-display area, and wherein the pairof first protrusions and the pair of connectors are connected to the padunit.
 13. The OLED display of claim 7, wherein the TFT comprises anactive layer, a gate electrode, a source electrode, and a drainelectrode, wherein the gate insulating layer is disposed between theactive layer and the gate electrode, wherein the interlayer insulatinglayer is disposed between the gate electrode, the source electrode andthe drain electrode, and wherein the gate insulating layer and theinterlayer insulating layer extend from the display area to thenon-display area, and wherein the thin film encapsulation layercomprises at least one inorganic layer contacting the gate insulatinglayer or the interlayer insulating layer outside the dam.
 14. The OLEDdisplay of claim 13, wherein the at least one inorganic layer has aportion contacting a top surface of the substrate.
 15. An organiclight-emitting diode (OLED) display, comprising: a display unitcomprising a display area and a non-display area surrounding the displayarea; a voltage line comprising a first voltage line and a secondvoltage line, wherein the second voltage line is formed in thenon-display area and surrounds at least a part of the display area; aplurality of dams formed in the non-display area and surrounding thedisplay area; and a metal layer separated from the first and secondvoltage lines and located adjacent to the first voltage line, whereinthe dams overlap the metal layer, the first voltage line and the secondvoltage line on a plan view, wherein the first voltage line disposed inone side of the display area, wherein the first voltage line comprises apair of first end portions and a pair of first connectors respectivelyconnected to the pair of first end portions, wherein the metal layer isdisposed between the pair of first connectors, and wherein the damsoverlap the first connectors on the plan view.
 16. The OLED display ofclaim 15, wherein the metal layer is electrically insulated from thesecond voltage line.